Storage-battery electrode.



I ATENTED MAR. 17, 1908-' T; A. EDISON. STORAGE BATTERY ELECTRODE.

APPLICATION FILED MAR. 30, 1905.

fizvenZor.

UNITED STATES PATENT ()FFICE.

'llllMiASA. EDISON; 0F LLEWELLYN PARK, ORANGE, NEW JERSEY, ASSIGNOR TO EDISON STORAGE BATTERY COMPANY, or WEST ORANGE, NEW JERSEY, A (ORPORATION or NEW .1 ERSEY.

STORAGE-BATTERY ELECTRODE. r

To all whom it may concern:

Be it known that I, THOMAS AhEmsoN, of Llewellyn Park, Orange, in the county of Essex and State of N ewJersey,have invented a certain new and Improved Storage-Battery Electrode, of which the following is, a descri tion.-

y invention relates to an improvedstorage battery electrode, wherein the active material is associated with minute flakes or foils of an ,insoluble metal or metals, preferably cobalt-or an alloy of nickel and cobalt, or nickel alone.

In using metallic conducting flakes for ad-- mixture with the active material, difiiculties have been e erienced, due in the first place, to the fact t at electrical contact between the metallic flakes and between the flakes and the pocket walls is generally poor and difiicult to maintain, except under considerable pressure, and in the second lace, to.the

fact that opportunity is ofl'ere within the mass for the tapping of gas, resulting in separation of the active articles and bulgi of the pocket walls, to urther increase the iflicultles of contact. The latter objection is more pronounced when the battery solution -employed is uite concentrated and hence in the best con ition for high economy, owing to the viscous character ,thereof. Consequently, there has heretofore been a limit at which the further concentration of the solution cannot be carried without serious objection.

M object is to provide an improved stor age attery' electrode, wherein metallic contacts withm the electrode are entirely done away with, and wherein very muchless opportunity is offered for gas pressure due to solutionviscosity, and or trapping of gas with the objections noted.

To this end, the invention consists of a storage battery electrode, wherein the flakes of conducting metal or metals are welded together and to the pocket walls, if used, presenting a highly diversified cellular integral structure with a very small weight of metal, in which the active material is intimately contained, the process of-manufacture bein such that the active'material is introduce within the cellular structure after the formation of the latter, so that obviously, freepassage will be allowed for the escapeof any gas generated in 'situ. By so constructin the Specification or Letters Patent.

Application filed latch 80, 1906. Serial No. 252,929.

Patented March 17-, 1908.

conductin metal that it shall constitute a honeycom or sponge-like cellular structure within the pocket or other electrode element and by allowing free op ortunity for the escape ofgas-generatedm erein, the tendenc of the electrode mass, as awhole, to swell s very largely reduced, and for this reason the necessity of employing expensive and highly elastic steel is overcome; moreover the cheaper steel, if used, can be more readily and economically perforated. Furthermore,

employing an integral metallic spon e- 1 e 'conductm system, as explained, t e conductivity 0 the latter'will be always constant and as it presents cells of minute size, the thickness of active material in contact with any part of the conducting system will be relatively slightiprobably not greater than one or two articles thick) so thatit will be necessary or the current to traverse paths of the minimum length througlithe active particles, thus allowing an enormously hi h discharge rate;

y impregnating the cells of the conducting structure, as hereinafter described, I am furthermore enabled to remove the active material whenever necessary, after which the conducting structure may be cleaned by hydrogen and reused with fresh active material. Furthermore, the process of forming the conducting metallic sponge or cellular structure within the ockets, as ex lained, also results in the wel ing'of the oc et sec-j tions so that a structure will he secured wherein all metallic contacts are eliminated, the advantages of which are obvious.

Assuming the mechanical make-up of the electrode to be substantially like that illustrated in my Patent No. 704,305, dated July 8, 1902, I proceed substantially as follows:

first take a suitable refractory material capable ofbeing readily dissolved when de sired, such as magnesium oxid, and mix it with a small quantity of water containin a little carbonate of soda or other suita le binder. Only enough water is added to slightly moisten the oxid, so that after thorough mixing the oxid shows a tendency to cake together or pack slightl This mass is then molded into thin ca es under hyto a white heat, so as to consolidate the same ,and make them fairly hard. The cakes aretl'iei crushed-to form granules of fairly definite size which are then screened. Those articles passing a 20 mesh screen and recctedby an mesh screen are first with water, then dried, and are then mixed with a suitable sticky material,- preferably stiff molasses, until the exterior surface of all the particles is coated with the latter. I now add the thin metallic flake-like conductin metal or metals (preferably cobalt or a cobalt-nickel alloy, or nickel alone) in the form of relatively small films or scales in substantially the profportion of twenty-four arts by weight 0 the granular oxid and We parts by weight of the conducting metal, and intimatel mix the same. Owing to the presence of t e thin sticky film on each of the oxid anules, the surface thereof will be coated with the flake-like metal, so that when the mixing is complete the resultin mass shows to the eye none of the white oxi but appears to consist entirely of metallic anu es. The metallic flakes referred to may be made in any suitable way; for example, thin sheets of cobalt or nicke or a nickel-cobalt alloy made by fusion, may be rolled into flakes, oil being used to prevent sticking, as is well known, for instance, in the art of making bronze powder. Or instead, the hydroxid of either metal, or the mixed bydroxids of both metals in the proper proportion can be reci itated in t e usual way, washed, drie an anulated to the proper size, and after re uction by hydrogen or otherwise, passed between rolls with oil to form the flakes, as I describe in my Patent No. 827,717, granted Au t 7, 1906. In either case, it is desirab e to anneal the flakes two or more times between the passes of the rolling operation in an inert as, preferably hydrogen,' at a red heat. fter the flakes are formed, it is preferable, in order to increase their. bulk, to ass them between very fine crimping rolls by which they will be crimped, corrugated or otherwise distorted, or between rolls of very small diameter by which they will be curled or formed into minute curved flakes. Or instead, the flakes or foils may be made by a process of electro-deposition, as I describe in my Patent No. 821,626, granted May 29, 1906, in which event the su sequent crimping or curling operation may be dispensed with, since electro-deposited films naturally assume curved or coiled forms. For construction of the flakes or scales, or foils, I find that metallic nickel, altho h perfectly insoluble,

possesses the objection that good contact with the active material cannot be secured unless an undesirably high pressure is employed. This fact can be possibly attributed to the formation of an invisible film of nonconductin oxid by the action of electrolysis on the nic el flakes. Metallic cobalt on the other hand, is not open to this objection, for

' altho h its surface is slightly attacked by el'ectro ysis, yet good contact with the active particles is secured, even when no pressure is used other than the weight of the particles themselves. It is possi 1e, however, that the electrolytic action on the metallic flakes, if made wholly of cobalt, might, in a 10 time gradually disintegrate t e same, an for this reason I consider it undesirable to rely on metallic cobalt alone. I therefore prefer to make use of a nickel-cobalt alloy,

containing say-60 per cent. of cobalt and 40 per cent. of nickel. With such an alloy good contact with the active material will be secured b the mere'weight of the latter without ad itional pressure, while at the same time, oxidation of the cobalt will not penetrate into the allo to a harmful extent, so that the flakes wil preserve their metallic identit This desirable characteristic of the nic el-eobalt alloy is present even when the proportions of 'the two metals are widely varied.

The mixture secured bv adding the flakes to the coated particles is dried, and is preferabl introduced within the usual sectional Koo ets which are assembled in the grid and ydraulic pressure applied, as I descri in my said patent, to e age the pocket sections together and lock t latter, firmlv in the grid. The grid is now immersed iri slightly alkaline water (sava two per cent. solution of potassium hydroxid) until the molases has entirel percolated outof the mass which can lie effected by several c of the solution, after which the electrode is "again subjected to pressure. The electrode is now dried, and is placed in a'retort through which hydrogen is passed, and bro ht to a bright yellow heat. The presence if the by n atmosphere revents any oxidation of t e metal at the eat used, and the two sections of each ket will be thus welded to one another, an the metallic flakes or foils distributed throughout the mass will be also welded together and to the ket sections. In other words, by this weidfig operation, integrality of the entire metallic parts of the electrodes is secured, so as to entirely eliminate metallic. contacts in the electrode system. Furthermore, byewelding fiber the metallic flakes within t pockets, (i930 tunitg for the escape of gas is allowed, ucingt edangerofgaspressurearisinginthe active mass, and permitting grade of steel to be employed. It will of course, be understood that the heat applied is sufficient only to effect a welding operation metallic filmsprlor toand during the weld a much cheaper in water or otherwise recovered.

oxid inwany suitable way, as for example, in

diluteuac'etic acid. which does not sensibly attack the metallic parts.

7 As a result of the operations so far followed, 0

I obtain a structure in which the usual erforated pockets are loose] filled with a ne, quite 'soft, pithy, rea ily compressible, sponge-like or honeycomb mass of insoluble metal or alloy, presenting innumerable cells all connected-together, and, in bulk occupying only a fraction .of the available space inclosed by each pocket and of such a character as to make ood contact with the active material. A ter the acid has been washed out and the electrode dried, the electrode plate is preferably subjected in a hydrogen atmosphere to heat, insufficient to effect a further welding, but sufiicient to effectively clean all the metallic surfaces and reduce any oxids resent, so as to permit perfect contact with t e actiyematerial (for example, nickel hydroxid) which it now becomes necessary to introduce within the cellular mass. is done by introducing the electrodes in a closed chamber connected to a vacuum pump, and whose walls may be heated, for

instance, by a steam jacket. -I now introduce withinthe inclosed chamber by means of a pum a saturated solution of a suitable nickel sa t, referably an ammoniacal solution of nicke hydroxid made by dissolving to saturation, nickel sesquioxid in ammonia. This saturated ammo'niacal solution enters at the bottom of the chamber and as the level rises all the ores or cells of the spongelike structure be filled with the same. The surplus solution is now withdrawn from the impregnating chamber, capillarity. preventing the escape of the solution from the sponge-like structure, the vacuum pump is operated, and heat is ap lied to quickly evaporate the'ammonia and water, leaving a deposit of nickelous hydroxid on the walls of the many cells, the ammonia bein absorbed l ly repeating these operations many times, the cells nav be. almost entirely filled with the active hydroxid, care being of course taken to use at all times a saturated solution, in order that the active material deposited within the cells shall not be dissolved out during the succeeding o erations. By I depositing the active material in successive layers on the walls of the cells, as explained, it is possible to so regulate the amount of active material thus introduced, as. to rovide ,numerous minute-connected channe s, extendi in all directions throughout the mass and eadi' to the surface thereof, and through whi dli any gas generated within the mass may freely escape. The electrodes thus formed are now removed, the exterior surfaces freedlfrom any oxid which may adhere to the same, and

This

after being subjected to pressure to consoli date the metallic sponge on the active material, are ready for use.

' It will be' understood that the requisite cellular-structure can be secured in other ways" than bythe process above indicated. For

instance, any other suitable inert refractory granular material capable of being dissolved or otherwise removed may be employed, in-

stead of a magnesium oxid, such as ignited tricalcic phosphate, in granular form. With this material the operations are the same as those followed with magnesium oxid. Itis also possible to omit the granular material, and introduce the corrugated or curved flake or foils loosely into the pockets b jarring and tamping, followed by welding 1n hydrogen, and imregnation with active material, as described in my Patent No. 854,200, granted May 12], 1907. I 1

'. Improved results will be secured when the pocket sections and grid of each electrode are plated with cobalt nickel alloy, instead of with nickel alone, as heretofore, since such an alloy materially increases the character of contact. 'Such an alloy may be substantially 50 per cent. cobalt and 50 per cent.

nickel, and may be applied by electro-deposition in any suitable way. After this cobalt-nickel plating has been ap lied, the metal p'arts'arepreferablywelde liv the application of heat in ari inert gas,'such as hyof ten drogen, so as to relieve any condition sion in the deposited coating.

In the accompanying drawing, forming art of this specification, and inwhich simiar parts are represented by the same refer-.

ence numerals, I illustrate in Fig. 1, a sec tional view on an enlarged scale, on theline l1 of Fig. 2,-a portion of a grid with'a sectional pocket therein of the t ple disclosed in my Patent No. 704,305, date uly 8th, 1902, with a sponge-likel conducting structure there in obta ned as described, and Fig. 2, a plan view of a portion of a grid on a somewhatsmaller scale, showing one of the pockets in place. In these drawings, 1 represents the grid, having a series of openings 2 therein, 3 and 4 are the perforated sections of the pocket, crimped in position within each of said openings, and 5 is the sponge-like conduct ing mass.

While I prefer to employ scales or flakes of a suitable metal or alloy for forming the sponge-like conducting stmcture surrounding the active mass, as I thereby obtain the greatest porosity with the least weight of metal. the same process may be carried out with the metal or alloy in powdered lorm, although at a sacrifice of weight, since ob,- viously the relationbetween the bulk of the metal or alloy and the cubical contents of the cells or pores, would be much less in the case of the metallic owde'r than in the case of metallic scales, akes or foils, so that theuse seas of metallic powder would probably be commercially inapplicable. Finally, 1t will be understood that the sponge-like conducting structure may be used for sup orting the active material independently o the usual perforated pockets in which case the latter may be omitted. I consider it preferable, however, to use the rforated metallic pockets as they materially strengthen the construction of the electrode, and effectively prevent the active material from scaling oil or falling out of the exposed cells or pores at the surface of the spongy mass. Furthermore, the perforated pockets protect the spongy mass effectivel' against accident. since the mass is somew at fragile and of but slight tenacity.

I do not claim herein the specific method described of forming the spongy or honeycomb structure by the loose introduction of the flake-like or foliated material into the pocket or rec-e tacle, since this specific process is descri and claimed in my Patent No. 854,200, granted May 21, 1907. There are, however, claims in my present application, the language of which is generic enough to include thespecific process described in my said concurrent case.

Neither do I claim herein any specific process for making flakes or foils, since such rocesses are specifically described and claimed in my Patent No. 821,626, granted May 29, 1906, referring to the method of making said flakes by electro-de osition, in my Patent No. 827,717, grante August 7, 1906, referring to the making of said flakes by precipitation. and in my Patent- No. 821,627. granted May 29, 1906, referring to the making of said flakes by sublimation. Finally, I do not claim broadly herein. the employment of cobalt or a nickel-cobalt alloy, as material fromwhich to make the flakes o'r films, since this suggestion is covered broadly in my Patent No. 857,929, granted June 25, 1907. In my present application, however, I make claims to the use of cobalt and cobalt-nickel alloy in the make-up of conducting structures, when the latter are of a sponge-like or honeycomb formation.

Having now described my invention what I claim as new therein and desire to secure by Letters Patent is as follows 1. A support for the active material of an alkaline battery, comprising a non-active metallic conducting structure in the form of minute connected irregularly disposed and shaped cells, having filmy or scale-like walls, subsltantially as and for the purposes set fort l.

2. A support for the active material of an alkaline battery, comprising a multitude of conductin metallic flakes welded together to form a cellular integral structure, substantially as set forth.

3. A support for the active material of an alkaline battery, comprising a cellular nonactive metallic conductin structure composed wholly or in art 0 metallic cobalt, substantially as set orth.

4. A support for the active material of an alkaline battery, comprising a multitude of conducting metallic particles welded together to form a cellular integral structure, composed wholly or in part of metallic cobalt, substantially as set forth.

5. A support for the activematerial of ali alkaline battery, com rising a multitude of conducting metallic akes welded together to form a cellular integral structure, composed wholly or in art of metallic cobalt, substantially as set orth.

6.- A support for the active material of an alkaline battery, comp a cellular conducting structure com of nickel-cobalt alloy, substantially as set forth.

7. A support for the active material of an alkaline battery, com risi a multitude of particles of nickel-co t' oy, welded to-' gether to form a cellular integral structure, substantially as set forth.

8. A support for the active material of an alkaline battery, comprising a multitude of to form a cellular integral structure, an tan-. tially as set forth.

9. In a storage battery having electrolyte, an electrode, comprising a cellular non-active metallic conducting structure havi filmy or flake-like walls and active material carried within the same, substantially as set forth.

10. In a storage battery having an alkaline electrolyte, an electrode, comprising a cellular non-active metallic insoluble conducting structure having filmy or flake-like walls, and active material carried within the same, substantially as set forth.

11. In a storage battery having an alkaline electrolyte, an electrode, comprising a cellular metallic insoluble conductin structure having filmy or flake-like wa s and nickel h droxid carried within the same, -substant1ally as set forth.

12. In a storage battery having an alkaline electrolyte, an electrode, comprising a multitude of conducting metallic fla es welded together to form a cellular inte al structure and active material carried wit in the cells thereof, substantially as set forth.

13. In a storage battery having an alkaline electrolyte, an electrode, com risi a multitude of conducting metallic fla es welded together to form a cellular integral structure and nickel hydroxid carried within the cells thereof, substantially as set forth.

14. A storage battery electrode, comprising an inclosing pocket with perforated l walls, a cellular-metallic conducting strucan alkalineflakes of nickel-cobalt alloy welded to ether 7 carried by Walls, a multitude of metallic within said pocketfandwelded together to to the walls o'f'the structure wit ture having diversified minute cells inclosed by said wa s, and an active material the cells thereof, substantially as set forth.

l A storage battery electrode, com pris ing an inclosing pocket, having perforated walls, a cellular conducting structure having highly diversified minute cells inqlosed by said walls and integral with the same, and active material carried within the cells thereof, substantially as set forth: g

16. -A storage battery electrode, comprismg walls, a cellular conducting structure'having highly diversified minute cells inclosed by said walls and inte al with the same, and nickel hydroriidcarried within the cells thereof, substantially as set forth.

ing an inclosing pocket havi form a sponge-like 'or cellular structure and active'mat'erlal carried within the cells thereof, substantially as set forth. g 18. A storage battery electrode, comprising an inclosing pocket vhavin perforated walls, a multitude of metallic fia within said pocket and weldedztogeth'er'to ,form 'a sponge-like orcellular structure and nickel hydroxid carried within the cells thereof, substantiallyas set forth. j o 19. A storage. battery electrode,

walls, 'a multitude of conduct' 'scales or films within the pocket,.welded togethenand te'ria fc'arried within the {eellsltliereoff sub stantiallyasf set forth.

20. A storage batteryj electrode," compris ing an nclosing pocketlhavin'g perforated 'walls, f a multitude of conducting scales or films within] the pocket, welded togethera'nd to thewalls, of the pocket to form an inte al" sponge-like cellular structure and nickel oxid carried within the ,cellsthereof, sullstantially asset forth. 1 21. 'A storage battery electrode, comprising a sectional inclosing pocket having perforated walls, the sections of which are welded together, as onge-lik'e metallic iconducting iiin'said walls and active matean inclosing pocket, having perforated structure wit 1-7. A storage battery-electrode, compris perforated es or scales es or scales" I I k g compris- I ing mclosmg pocket I havingfperforated pocket to forrnf an, integral forth.

spo e -like cellular structure Midfactive mas .welded together and to the pocket tially as set forth; 22. A storage battery'electrode, comprising a sectional inclosing pocket having .pe'rforated walls, the sections of which are welded together, a s onge-like metallic conductin structure wit saidpocket and integra with the walls thereof, and active material within the cells of the'conducting structure, substantially as set forth. 5 I g 23. A-storage battery electrode, compris :rial carried within the cells thereof, substaning a sectional inclosing pocket having perforated walls, the sectionsofwhich are welded together, a s onge-like metallic conducting hin said pocket and integra with the walls thereof and nickel hydroxid the conducting structure, substantially asset-forth g 24., A'storage battery electrode, compris- I to ether, a multitude of metallic conducting fl fires within said pocket, said 'flakes being welded together to form a sponge-like or cellular structure, and active material carried 'ing a sectional inclosing pocket having perfo-- rated walls, the sections of which are welded within the cells thereof, substantially as set.

forth.-.. v

25. Astorage battery electrode, comprise ing asectional inclosing pocket having perforated walls, the sections of whichare welded to ether, a multitude of'conductin metallic flaies wlthin the pockets, said Ha es being welded together and to the pocket'walls to form an integral conducting sponge-like or cellular structure and active material carried within the cells thereof, substantially as set w 26. A storage battery electrode, comprising a sectional inclosing pocket having perforated. .walls, the sections of which are welded gfther, a multitude of conductin metallic a es within the pockets, said fla es being walls to. 

